function countDown(a, b, c) {
    function countDown(options) {
        var target_d = new Date(options.year, options.month - 1, options.date);
        var target_t = target_d.getTime();
        var now_t = Date.now();
        var reduce_t = target_t - now_t;
        if (reduce_t < 0) {
            return false;
        }
        var day = parseInt(reduce_t / 864e+5);
        var ms = reduce_t % 1e+3;
        var sec = parseInt(reduce_t / 1e+3 % 60);
        var min = parseInt(reduce_t / 6e+4 % 60);
        var hours = parseInt(reduce_t / 36e+5 % 24);
        return {
            day: day,
            ms: ms,
            sec: sec,
            min: min,
            hour: hours
        }
    }
    function cd() {
        var res = countDown({
            year: 2020,
            month: 11,
            date: 31
        });
        document.querySelector(a).innerHTML = res.hour;
        document.querySelector(b).innerHTML = res.min;
        document.querySelector(c).innerHTML = res.sec;
    }
    setInterval(cd, 1000)
    cd();
}


